The proposed research program is a continuation of a current project in the development of materials and components leading to the design of new miniature fiberscopes for visualization, biopsy, and surgery. It builds on existing unique technological developments in the Fiber-Optics Research Laboratory of Northwestern University such as the preparation of microlenses (0.5 millimeter in diameter) and improved methods of fabrication of miniature rigid and flexible imaging multifibers made of glass and plastics. The design of specific instruments is conducted in close cooperation with medical researchers from the earliest concepts in order to appropriately direct the relevant developments in materials and components. The choice of instruments and the construction of their prototypes are diverse to assure the widest spectrum of functional design, thus allowing for effective extensions into other designs. A close cooperation with industry has been established to provide for a speedy and effective transfer of the resulting design methods. Results of work in the development of specific prototype instruments and their clinical applications are disseminated through publications in medical and engineering periodicals and through papers read in appropriate workshops and seminars. It is the intention that the research program serve engineering and clinical researchers in the development of optical instrumentation in medicine.